Ultrasonic power apparatus



Sept. 19, 1967 A. A. SNAPER ULTRASONIC POWER APPARATUS 2 Sheets-Sheet lFiled May 21, 1965 OSCALLATQR R O T A L m C S O v0 .e m e .7M 7 l/ www@@MMM M7 www@ Q m vnf r 6 6 ,l f ih h .|ll *hm/ .l| IO 5 Hf Hf m m R R 1w m m u m n U m M u c M C m u 5 n u ,D n o o m m w Q m illy@ {fd}/A/l/E/VTOI? A L V//v A. SA/Apf/e A. A. SNAPER ULTRASON I C POWERAPPARATUS Sept. 19, 1967 2 Sheets-Sheet 2 Filed May 2l, 1965 VENTO/2 4.4V//v A SNAPEQ By @ML E. @11% A 770/2NEY w mb//fm/ e MNHWWQ n i J 5 L fr5 2 3 4 .I .-.Illl .0H VO L /Hhn rmi; j huh \/Vul||m\ j j .iv 1 .z F.Huf .Hf Hf Hf R om n R n R R o O m O q Y m M M m m A A L L .LLL u L u,.LL m m Q u L u LL O d u O O u O O m q L w w mL w m United States PatentO 3,343,010 ULTRASONIC POWER APPARATUS Alvin A. Snaper, 9722 CasabaAve., Chatsworth, Calif. 91311 Filed May 21, 1965, Ser. No. 457,723 2Claims. (Cl. S10-20) ABSTRACT OF THE DISCLOSURE This invention dealswith ultrasonic means for driving a shaft to produce mechanical power.The ultrasonic vibrations produced also have the effect of producing anair cushion between the shaft and the means to considerably reducefriction.

The present invention relates in general to the field of ultrasonics,and more particularly relates to an ultrasonically-driven motorapparatus.

The point of novelty of the present invention is in employing ultrasonicpower to rotatively drive a shaft-like member at an angle to theultrasonic gun that drives it and without, or substantially without,physical contact existing -between the ultrasonic gun and the shaft-likemember. More particularly, in a preferred embodiment of the invention,electrical oscillations supplied by an oscillator at an ultrasonicfrequency are converted to corresponding ultrasonic mechanicalvibrations by means of a transducer coupled to the oscillator. Anacoustical matching block is mechanically bonded or affixed to thetransducer and, therefore, vibrates with it, and it has been discoveredthat when a hole is placed in the block at an angle to its longitudinalaxis and a shaft placed in the hole, the shaft will rotate and will doso with very little, if any, contact with the sides of the hole.Consequently, a new type of motor apparatus has been invented that hasmany advantages associated with it not found in the prior art.

More specifically, the present invention makes it possible to drive adrill bit at an angle to the main body of the driving apparatus, forexample, a right angle which, in turn, expedites and facilitatesdrilling operations in places that are difficult to reach or almostinaccessible, lsuch as the hollow of a cylinder of a relatively smalldiameter. A further advantage obtained from the present invention isthat no lubrication is needed between the walls of the hole and theshaft mounted therein, it having been found that so little contact ismade between them. Thus, embodiments of the present invention would finduseful application in space activities where the proper and continuedlubrication of moving parts has been and will continue to be a diicultproblem. Still another advantage of the present invention, when it isappraised in the light of the prior art, lies in the fact that it makesit possible for a number of shafts to be driven simultaneously by asingle apparatus. In the case of a drill, for example, this Would meanthat several drill bits, either of the same or of different diameters,could be used at one time.

It is, therefore, an object of the present invention t provide anultrasonic apparatus for rotatively driving a shaft-like member.

It is another object of the present invention to provide an ultrasonicmotor.

The -novel features which are believed to be characteristic of theinvention, both as to its organization and method of operation, togetherwith further objects and advantages thereof, will be better understoodfrom the following description considered in connection with theaccompanying drawings in which several embodiments of the invention areillustrated by way of example. It is to be expressly understood,however, that the drawings are for the purpose of illustration anddescription only, and are not intended as a definition of the limits ofthe invention.

FIGURE 1(a) is a top view of a preferred embodiment of the invention;

FIGURE 1(b) is a side view of the same embodiment;

FIGURE 1(0) illustrates a rst modification that may be made in theconstruction of said preferred embodiment;

FIGURE 1(d) illustrates this first modification in somewhat greaterdetail;

FIGURE 1(e) illustrates a second modification that may be made in thispreferred embodiment;

FIGURE 1( f) illustrates still a third modification that may beintroduced in it;

FIGURE 2 illustrates a second embodiment of the invention in which theshaft is either the same size 0r shorter than the depth of the hole;

FIGURE 3 illustrates a third embodiment of the invention in which thehole and the shaft therein have been adapted to provide useful servoapplications; and

FIGURE 4 illustrates still a thirdembodiment of the invention in which amechanism is combined with the shaft to permit the interchangeability ofparts.

For a consideration of the invention in detail, reference is now made tothe drawings wherein like or similar parts or elements are given like orsimilar designations throughout the several figures. In FIGS. l(a) and1(1)), the embodiment is shown to include a transducer 10, in this casea magnetostrictive transducer in the shape of a core, that is coupled toa variable oscillator 11 by means of primary and secondary windings 12and 13, respectively, wound upon the core and connected to theoscillator. For reasons that are Well known in the art, magnetostrictivetransducer 10 is suitably biased by means of a pair of permanent magnets14a and 14b, respectively mounted on opposite ends of the transducer.Bonded or otherwise rigidly affixed to the forward end of transducer 10is an acoustical matching block, generally designated 15, that may bemade of metal, ceramic, glass or any material for that matter that hasgood or efficient acoustical transmission properties. The shape of thematching block is relatively unimportant and, therefore, it may be arectangular block or plate, it may be triangular in shape, or, on theother hand, it may be given a step-down configuration with a narrow nose15a protruding from a larger and wider base portion 15b as is shown inthe gure. However, whatever its shape, the matching block should bedesigned for maximum power transfer, taking into consideration theparameters of the transducer, the power requirements and the range offrequencies under which the device is or may be operated. In the matterof frequency, any ultrasonic frequency from about 18 kilocycles persecond to approximately 300 kilocycles per second may be employed, 20kilocycles per second, 40 kilocycles per second and 85 kilocycles persecond being examples of typical operating frequencies.

Extending through nose 15a, preferably at its forward end, is a hole 16through which there extend-s, in a nonfrictional t, a shaft 17.Elaborating somewhat on what is meant by a nonfrictional lit, the shaftcannot be mounted too tightly in the hole or else it will not rotate, orif it does, it will do so only with great difficulty. On the other hand,the spacing between the shaft and the walls of the hole cannot be toolarge or else the shaft will wobble as it rotates. Accordingly, asomewhat loose tit should be provided between these two extremes. Holediameters varying from 0.003 inch to 0.375 inch have been employedsuccessfully, and there is no reason t0 assume that smaller or largerdiameters could not be used as well.

To prevent the shaft from falling through the hole at any time, a pairof retaining lips are therefore mounted on the shaft on either side ofnose 15a, the lips being designated 18a and 18b. The shaft itself, aswell as the lips thereon, may be made of any sturdy material, such asmetal, ceramic, rigid plastics, etc. A gear or some other suchutilitarian device would normally be mounted on one or both ends ofshaft 17 so that the rotation of the shaft may be utilized in apractical manner. However, such utilitarian devices are not considered apart of the present invention and, furthermore, the manner in which theywould be mounted on or otherwise coupled to the shaft is so well knownthat it was not deemed necessary to an understanding of the invention toshow them. Considering now its operation, the electrical oscillationsgenerated by oscillator 11 are applied via windings 12 and 13 totransducer 10 which, as is well known, thereby begins to mechanicallyvibrate in a longitudinal direction at the same or substantially thesame frequency as the electrical oscillation. As a result, acousticalblock 15 also begins to vibrate in the same direction and this, 1n turn,it has been discovered, causes shaft 17 to rotate at a relatively highspeed. Consequently, the electrical energy produced by the oscillatorhas now been converted to mechanical energy of a rotative nature, anduseful work can be done with it, as in the case of any motor. Thus, ifone or more gears are mounted on the shaft, they may be used to drivestill some other pieces of apparatus. On the other hand, if the end ofthe shaft is a drill bit, then, because of the relatively smalldimensions of nose 15a and because of the angle that the drill bfi-tforms with the nose, holes may be drilled in places that would normallybe inaccessible or difficult to reach with ordinary drills. Rotationalspeeds .of 3,600 r.p.m. and 12,000 r.p.rn. for the shaft have alreadybeen observed.

One further point should lbe made with respect to the operation of thisapparatus, namely, that in add-ition to the discovery that themechanical vibrations of acoustical block 15 cause shaft 17 to rotate,it has also been discovered that these same mechanical vibrations causea cushion of air to be formed between the shaft and the walls of hole16, as well as between nose 15a and retaining lips 18a and 18b, thatmaintains or supports the shaft in a central position in the hole, thatis to say, keeps it away from the sides of the hole. Thus, as a result,there is a minimum contact, if any at all, between the elements of theshaft and the acoustical matching block. A minimum of such lcontact hasalso been found to exist in an airless environment, such as in a vacuumchamber or in space, the explanation being that contact between the twoparts occurs only during a very small part of the entire oscillatory orvibrational cycle. It is thus seen that the present invention reducesfrictional forces to a minimum and thereby avoids the necessity ofproviding a lubricant for them.

In the FIG. 1 embodiment, the hole 16 has been described as goingentirely through the -bar or nose 15a with the shaft 17 extendingthrough the hole on both sides. However, this can be modified in themanner shown in FIG. 1(0) wherein the hole 16 is shown to go onlypartially through the nose. With this kind of modification, the shaftinserted in the hole normally is longer than the depth of the hole and,therefore, protrudes from one side. Thus, in this case, one end of shaft17 is laterally retained at one end by the nose itself, and on theotherend (not shown) by any well known device, such as a simple bearing,the utilitarian device, such as the gear previously mentioned, beingmounted on the shaft between the two supports. By way of a specificexample of how this could be done, reference is made to FIG. l(d)wherein two identical units of the present invention are shown bothdriving and supporting lshaft 17 in unison, a gear designated 20 mountedon the shaft between them. In other words, FIG. 1(d) illustrates how twoidentical units of the kind shown in FIG. 1(0), driven by the sameoscillator, may be combined to provide a motor drive in a substantiallyfrictionless manner.

The FIG. l embodiment may be modified in still other ways, as is shownin FIGS. 1(e) and 1(1). More specifically, as is shown in FIG. l(e), bar15a may be provided with a plurality of holes 16 of the kind shown bothin FIG. 1(a) and in FIG. 1(c). Hence, a number of shafts 17 may ybecoupled to and driven by a single acoustical matching block, each shaftand the elements mounted thereon performing -their functionssimultaneously with all the others. In FIG. 1(1), the modification isshown to consist of a hole 16 that is drilled through nose 15a at anangle other than that is to say, at an angle different than those of theholes previously discussed. Thus, the present invention has greatversatility and makes it possible to drive a shaft that is oriented inalmost any direction. Needless to say, hole 16 in FIG. 1(1) may be ablind hole as in FIG. 1(0) or extend all the way through as in FIG.1(11).

In the embodiment of FIG. 2, the hole 16 is a blind hole, that is tosay, it only goes partially through the bar, the shaft 17 positioned orinserted in the lhole being the same length as or even shorter than thedepth of the hole. When this embodiment is activated or operated in themanner previously described, shaft 17 moves out or is thrust out of hole16, and when deactivated, the shaft returns to or goes back into thehole. In this embodiment, therefore, the shaft extends itself from thehole when operation is initiated and rotates as before in this extendedposition. Upon deactivation, however, the shaft retracts into the holeand awaits the next cycle of operation, Assuming that the shaft would beproperly adapted for such purposes, an arrangement of the kind shown inFIG. 2 would be useful for internal drilling operations or as aninternal pin-locking device. It should also Ebe pointed out that heretoo, as in the case of the FIG. 1(e) modification, a number of holes 16and shafts 17 that extend and retract may be combined to simultaneouslyperform a number of functions. The same may be said with respect to theFIG. 1(1) modification so that, in the FIG. 2 embodiment, the holes maylikewise be slanted.

In the third embodiment, shown in FIG. 3, to which reference is nowmade, both the hole and the shaft are threaded to provided a specifictorque factor, Stated differently, since the hole and shaft arethreaded, when the mechanism is placed in operation, the shaft will windthrough the hole in one direction or the other at a predetermined speed.Where a specific rotation causes a predetermined extension or retractionof a shaft, such mechanisms are useful for servo applications. It willIbe recognized that the rate of movement of shaft 17 and, therefore, itsdisplacement in one -direction or the other not only depends upon thespeed of its rotation but also upon the pitch of the thread, both ofwhich may be accurately controlled.

A fourth and final embodiment of the present invention is presented inFIG. 4 and, as shown therein, it includes a shaft 17 that has aretaining lip 18b at one end and a chuck 21 rigidly mounted on the otherend. Chuck 21 is useful where interchangeable drill bits, gears, -orother mechanisms to be rotated are to be attached to the shaft.

The operation of the FIGS. 2, 3 and 4 embodiments is the same as it waspresented in connection with the FIG. l embodiment is that uponactivation of the transducer, the resultant vibrations of acousticalblock 15 cause the shaft to rotate at a fairly high speed and to do soin `a substantially frictionless manner for the reasons previouslygiven. Accordingly, to avoid being unduly redundant, nothing furtherneed be said about it. However, it should be mentioned that the speedand direction of rotation are a function of or, stated differently, areaffected by the frequency of lthe electrical oscillations. Hence, as maybe expected, both may be changed by changing the frequency and, as amatter of fact, at one point in the frequency spectrum the direction ofrotation of the shaft is reversed if the frequency is changed beyondthat point. However,

the location of that point is dependent upon the weight and size of theshaft, the configuration of the acoustical matching block, and similartype factors, with the result that this cross-over frequency isrespectively different for different structural arrangements and,therefore, cannot be specified at this time.

Although a number of particular arrangements of the invention have beenillustrated above by way of example, it is not intended that theinvention be limited thereto. Thus, for example, although amagnetostrictive type of transducer Was shown and described herein,other kinds of transducers, such as the piezoelectric kind, may be usedas Well. Accordingly, the invention should be considered to include anyand all modications, alterations or equivalent arrangements fallingwithin the scope of the annexed claims.

Having thus described the invention, what is claimed is:

1. Ultrasonically-driven motor apparatus comprising: means for producingelectrical oscillations at a frequency in the ultrasonic range offrequencies; a rectangularshaped transducer element coupled to saidmeans and operable in response to the oscillations therefrom tomechanically vibrate in the direction of its longitudinal axis at afrequency corresponding to that of the electrical oscillations; anacoustical matching block mounted on one end of said transducer elementand extending therefrom symmetrically with respect to the longitudinalaxis thereof, said acoustical matching block having a hole therein thatintersects said longitudinal axis at an angle therewith; and a shaftrotatably positioned in said hole and operable to rotate in response tosaid longitudinally-directed mechanical vibrations.

2. Ultrasonically-driven motor apparatus comprising: means for producingelectrical oscillations at a frequency in the ultrasonic range offrequencies; lirst and second rectangular-shaped transducer elementspositioned with their longitudinal axes parallel to one another, saidrst and second transducer elements being coupled to said means andoperable in response to the oscillations therefrom to mechanicallyvibrate in the direction of said axes at a frequency corresponding tothat of the electrical oscillations; first and second acousticalmatching blocks respectively mounted on one end of said rst and secondtransducer elements and extending in the same direction therefromsymmetrically with respect to said longitudinal axes, said rst andsecond acoustical matching blocks respectively having axially alignediirst and second holes therein that intersects said longitudinal axes atan angle therewith; and a single shaft rotatably positioned in saidholes and operable to rotate in response to the mechanical vibrations ofsaid transducer elements.

References Cited UNITED STATES PATENTS 3,058,218 10/1962 Kleesattel etal 310-26 X MILTON O. HIRSHFIELD, Primary Examiner. D. F. DUGGAN,Assistant Examiner.

1. ULTRASONICALLY-DRIVEN MOTOR APPARATUS COMPRISING: MEANS FOR PRODUCINGELECTRICAL OSCILLATIONS AT A FREQUENCY IN THE ULTRASONIC RANGE OFFREQUENCIES; A RECTANGULARSHAPED TRANSDUCER ELEMENT COUPLED TO SAIDMEANS AND OPERABLE IN RESPONSE TO THE OSCILLATIONS THEREFROM TOMECHANICALLY VIBRATE IN THE DIRECTION OF ITS LONGITUDINAL AXIS AT AFREQUENCY CORRESPONDING TO THAT OF THE ELECTRICAL OSCILLATIONS; ANACOUSTICAL MATCHING BLOCK MOUNTED ON ONE END OF SAID TRANSDUCER ELEMENTAND EXTENDING THEREFROM SYMMETRICALLY WITH RESPECT TO THE LONGITUDINALAXIS THEREOF, SAID ACOUSTICAL MATCHING BLOCK HAVING A HOLE THEREIN THATINTERSECTS SAID LONGITUDINAL AXIS AT AN ANGLE THEREWITH; AND A SHAFTROTATABLY POSITIONED IN SAID HOLE AND OPERABLE TO ROTATE IN RESPONSE TOSAID LONGITUDINALLY-DIRECTED MECHANICAL VIBRATIONS.